Technological Field
The present invention relates to an image forming device using a developer.
Description of the Related Art
Developers used for forming an image on a sheet in an image forming device include a one-component developer and a two-component developer. The two-component developer is constructed mainly by toner and carrier, and an external additive adheres to the surface of a toner particle.
The developer is made by various kinds of microparticles such as an external additive, and the performance of the developer easily changes according to a printing condition. When the performance of the developer changes and the fluidity of the developer deteriorates, the printing quality deteriorates. Consequently, the fluidity of the developer including the external additive has to be grasped accurately. For this purpose, for example, the following techniques are known.
Patent Literature 1 discloses a technique of measuring the amount of the external additive of a toner stemmed by a cleaning blade by a color discriminating sensor.
Patent Literature 2 discloses a technique of evaluating a toner layer state on a development roller, measuring the fluidity of the toner by a rotor method, and evaluating the fluidity.